Container filling machines are widely utilized in food product container packaging lines to quickly fill large numbers of containers. The efficient and reliable operation of the filling valves of these filling machines is critical to the process. Historically, the quick and economical filling of containers has been an object of a large number of devices. Container filling machines have evolved over the years from simple mechanisms to complex devices, yet with many features evolving and improving over time.
An example of an early device with advanced features is the U.S. Pat. No. 2,671,591 to Franz. Franz '591 discloses a mechanism for filling containers with a liquid, such as milk. The Franz '591 apparatus includes a central exhaust passage with an annular liquid fill port. A problem with Franz '591 is that it relies on gravity flow to fill the bottle, after the air pressure with the bottle equalized with the air reservoir above the filling liquid. Franz '591 fails to provide a mechanism that can fill at higher flow rates.
The filling of a container with carbonated liquids requires a pre-pressurization of the container to prevent foaming. This pre-pressurization step is not required in filling containers with non-carbonated liquids. Carbonated liquid filling mechanisms, though showing aspects potentially applicable to noncarbonated liquid filing mechanisms, typically all fail to efficiently operate in non-carbonated systems.
Some carbonated liquid fillers are notable in that they include features that would be desirable in no-carbonated liquid fillers. An early example of a carbonated system filling device is the U.S. Pat. No. 3,460,589 to Justis. Justis '589 shows a filling head apparatus for filling containers with carbonated beverages. Justis '589 teaches the flow of a liquid through a valve's central filling tube, while also injecting an inert counter pressure gas through the valve's concentric outer tube. The filling of a bottle with liquid from the central filling tube appears to improve the filling mechanism. However, Justis '589 also rotates a valve head rotates above the bottle to coordinate the counter-filling of the gas and filling the bottle with the liquid. This rotating valve of the Justis '589 device is quite complex and includes bottle pressurization features that are not required in non-carbonated filling systems.
A later example of carbonated system filling devices is shown in U.S. Pat. No. 4,442,873 to Yun. Yun '873 also shows a counter-pressure, carbonated liquid filling mechanism. Yun '873 includes a less desirable central vent tube that is utilized with a concentric liquid filling valve. Although Yun '873 is another counter-pressure valve, it does show a simplified configuration that avoids the complex cams and valves of many previous patents. However, the Yun '873 valve system includes a complex array of bias springs that together operate to control the action of the valve. Yun '873 fails to provide an easily adjustable valve with the ability to easily fine tune and adjust the actions of the valve.
U.S. Pat. No. 5,139,058 to Yun shows an improvement in a counter pressure filling mechanism. Yun '058 is similar to Yun '873, but adapted for cans rather than bottles. Yun '058 also includes a central vent tube that is utilized with a concentric liquid filling valve, but again, as with Yun '873, fails to provide an easily adjustable valve with the ability to easily fine tune the actions of the valve.
Additionally, comparing Yun '058 to Yun '873, it can be seen that it is presumed that significantly different mechanism are required to fill bottles, as compared to cans. A new container may be desired for a variety of reasons; to fill a market niche, for example, or simply to reduce expense. Typically, any new container type requires extensive retooling and filling valve modification or replacement. A universal valve for a variety of container types would be very desirable, and enable a filling line to quickly respond to consumer demand, market niches and improved container designs.
Another non-carbonated liquid filling valve is typified by the "BM8316" valve, produced by U.S. Bottlers Machinery Company, of Charlotte N.C., U.S.A. The BM8316 valve includes a central filler stem that is mounted to a filling machine. The filler stem is received within an exhaust manifold, which slides upward along the filler stem, toward the filling machine to expose the head of the filler stem when the valve is inserted into a bottle. The bottle impacts a flange at the base exhaust manifold and forces the exhaust manifold up to reveal the filler stem into the bottle. As the filler stem supplies a liquid into the bottle, the air within the bottle is exhausted through the annular space between the filler stem and the exhaust manifold. A biasing spring is included on the top of the exhaust manifold maintains the filler stem in a retracted position within the exhaust manifold, when the flange is not supported by the bottle.
The BM8316 valve also has several problems. The biasing spring of the BM8316 can not be easily adjusted. It provides a single, predetermined tension. Often, fine tuning of the spring's tension is required when the moving parts of the valve become sticky, bent or in some other way resist the sliding of the filler stem. A user can not compensate for an individual BM8316 valve's unique operation, without shutting down the filling line, removing the entire valve and either unsticking the valve or replacing the bias spring with a spring that may or may not be appropriate. A filling valve is needed that utilizes the superior center filling stem and overcomes the problems encountered in the function of conventional filling valves, as discussed above.
The filler stem of the BM8316 is a desirable feature for non-carbonated liquid filling. A valve configuration with the liquid filling from the center and the air exhausted from above and outside the filler stem is reliable and efficient. This center filling feature operates much better than the configuration found in more traditional, carbonated liquid type valves. Many traditional valves fill from a filler sleeve, positioned outside of a central stem, while exhausting air from the central stem. Such a central exhausting valve, for use with non-carbonated liquids, is typified by a "T-316" nozzle assembly, manufactured by Laub/Hunt Packaging Systems of Norwalk Calif., U.S.A.
In normal use, the undesirable center exhausting stems of the Laub T-316 valve have a problematic tendency to hang-up while retracting into the filler sleeve. This intermittent failure occurs because the filling liquid requires deflectors in the head of the exhaust stem to keep the filling liquid from short circuiting into the air exhaust ports, which are also on the head of the exhaust stem. The result of this hang-up, is a significant loss of product through spillage. Spillage also occurs in the Laub T-316 valve if the liquid fails to automatically shut off when the valve is removed from the container. By design, the center exhaust can not recycle liquid up the center stem. Instead any residual liquid squirts out from the valve as it clears the container and rotates to the next container in line. These basic design failings of the Laub T-316 valve result in significant losses of product. A filling valve is needed with the ability to minimize the loss of product when the valve is not filling a container.